Python shift data on every second row from one column to a new column-CodePudding

Newbie to python here...I have a dataframe like this

John
30
Mike
0.0786268
Tyson
0.114889
Gabriel
0.176072
Fiona
0.101895

I need to shift every second row to a new column so it should look like this

John   30
Mike   0.0786268
Tyson  0.114889
Gabriel 0.176072
Fiona   0.101895

Thanks in advanced!

CodePudding user response：

This one works for me and the code is easy to understand:

names = []
numbers = []
for i in range(len(df['Names'])):
    if (i % 2) == 0:
        names.append(df['Names'][i])
    else:
        numbers.append(df['Names'][i])

Now the construction of the dataframe:

new_df = pd.DataFrame([names, numbers]).T
new_df.columns = ['Names', 'Numbers']
new_df

The Output:

    Names   Numbers
0   John    30
1   Mike    0.0786268
2   Tyson   0.114889
3   Gabriel 0.176072
4   Fiona   0.101895

CodePudding user response：

another method that you can use by using subset

data=StringIO("""data
John
30
Mike
0.0786268
Tyson
0.114889
Gabriel
0.176072
Fiona
0.101895""")
old_df = pd.read_csv(data, sep=";")

new_df=pd.DataFrame({'name': old_df.loc[(old_df.index%2)==0,'data'].to_numpy(), 'value': old_df.loc[(old_df.index%2)==1,'data'].to_numpy()})

The result

    name    value
0   John    30
1   Mike    0.0786268
2   Tyson   0.114889
3   Gabriel 0.176072
4   Fiona   0.101895

CodePudding user response：

You can use divmod() to create a new index

df.set_index(list(divmod(df.index,2)))['Col'].unstack().set_axis(['Names','Numbers'],axis=1)

     Names    Numbers
0     John         30
1     Mike  0.0786268
2    Tyson   0.114889
3  Gabriel   0.176072
4    Fiona   0.101895

CodePudding user response：

Assuming df['col'] your column, a simple and efficient method would be to use the underlying numpy array to reshape:

out = pd.DataFrame(df['col'].values.reshape(-1,2),
                   columns=['Name', 'Value'])

Output:

      Name      Value
0     John         30
1     Mike  0.0786268
2    Tyson   0.114889
3  Gabriel   0.176072
4    Fiona   0.101895